Recent developments in soft tissue tumors.

This article reviews the clinicopathological features of several recently described soft tissue tumours, namely ossifying fibromyxoid tumour, angiomyofibroblastoma, epithelioid angiosarcoma, retiform haemangioendothelioma, intra-abdominal desmoplastic small cell tumour, spindle cell liposarcoma and low grade fibromyxoid sarcoma. Conceptual changes are also discussed. These include the relationship between Ewing's sarcoma and peripheral primitive neuroectodermal tumour, the proposed use of the term atypical lipoma for a subset of well differentiated liposarcomas, and the occurrence at a wide variety of sites of inflammatory myofibroblastic lesions of uncertain biological potential. In addition, advances in the study of soft tissue lesions at the molecular and cytogenetic levels are outlined, with particular emphasis on the recent identification of tumour-specific karyotypic abnormalities in a wide variety of sarcomas.